My guess?
Lit room: lots of things scattered around, colors, visual noise, over stimulating
Dark room: dark, not very visible, less/no noise, not (necessarily as) overstimulating
anecdote
The most relaxed I have ever been was in the middle of a huge snowstorm the wind died down and the flakes were huge, I couldn't hear anything, it was after sunset so once the flashlight was off it was pitch black, and with my coveralls, hoodie, thick coat, gloves and scarf I was warm and couldn't really feel much of the outside. I just laid down for about 40ish minutes, occasionally seeing the dim spot of headlights from a passing car. Similar concept, dark and quiet, muted external stimuli.
The masculine urge to wear pretty things and act feminine.
It's totally normal to wear women's clothes and research breast forms and practice walking in heels.... Right guys?... ^Guys?^